The proposed studies will continue our probe of the relationship between the rat liver steroid sulfotransferases--STI, STII, and STIII--and actions of glucocorticoids typified by cortisol. During the course of the studies envisioned for this year, we hope to: continue purification and characterization of STI and STIII; begin preparation of antisulfotransferases; and briefly test basic relationships between the sulfotransferases and glucocorticoid acids. (A) We will continue ongoing efforts to purify STI and STIII adequately for use in antibody generation. Presently the two enzymes have been purified about 1,000-fold from homogenate. Purification efforts--where necessary--will utilize a combination of endocrine manipulations and standard protein purification methods. (B) Studies of kinetic and physicochemical parameters of the purified sulfotransferases will be carried out. These will utilize standard methods and will add to our present knowledge of similarities and dissimilarities between the enzymes and allow us to estimate the suitability of the preparations for antibody generation. (C) Antibodies will be prepared by standard immunochemical methods. We hope to use them for development of a rapid immunochemical method for estimation of the amounts of the three sulfotransferases in tissue samples, planned to begin in year 3. (D) We will attempt to determine whether any of the sulfotransferases are equivalent to the cortisol binders we believe to be involved in cortisol-mediated enzyme induction. (E) We have presently implicated adrenals and gonads in control of STI, STII, and STIII production. We presently have evidence that the pituitary may be involved in control of the production of the sulfotransferases in a fashion that is not entirely related to its effects on adrenal and gonadal secretion. These studies will continue.